Traditionally, water detention and release systems for stormwater and/or septic purposes were constructed by burying concrete pipes, chambers or galleys in infiltration trenches backfilled with large gravel or crushed stone. Underground pipes supplied the system with water, which would be detained in the system until it naturally released into the ground underlying the concrete chambers. Concrete chambers or galleys are sturdy and are usually available at commercially acceptable prices from concrete precast companies. However, they are heavy and require heavy duty excavation equipment to move and install them. Also, they have definite sizes and shapes and are not conveniently modified or resized if an installation requires less than a complete chamber or galley or if during installation excavations it is discovered that there is buried rock or rock ledge that impinges on the planned position of the chamber or galley.
Water detention and release systems have also been constructed from plastic piping and molded plastic chambers. These systems are buried in trenches backfilled with crushed stone. Often such systems require large volumes of crushed stone to backfill the trenches. Plastic water detention and release systems are convenient to transport, install, and modify as needed during installation. However, the requirement for crushed stone beds to contain such plastic structures may cause challenges to the installer if there is limited clean crushed stone available in the area of the construction site at a commercially acceptable price.
What is needed, therefore, is an underground water detention and release system that utilizes both concrete and plastic materials to form a hybrid chamber that can retain large volumes of water. The desired system would be both stronger and more cost efficient than existing design approaches.